Project description:N6-methyladenosine (m6A) is the most prevalent internal RNA modification in mammalian messenger RNAs (mRNAs). While m6A has been shown to mark groups of mRNAs for coordinated degradation in various physiological processes, the relevance of m6A in affecting translation remains to be determined in intact biological systems in vivo. Here we show that, through its reader protein Ythdf1, m6A promotes a pulse of protein synthesis of target transcripts in response to neuronal stimuli in the adult mouse hippocampus, thereby facilitating learning and memory processes. Mice with genetic deletion of the Ythdf1 gene (Ythdf1-/-) exhibit learning and memory defects, as well as impaired hippocampal synaptic transmission and long-term potentiation (LTP). Selective re-expression of Ythdf1 in the hippocampus of adult Ythdf1-/- mice fully rescues the behavioral and synaptic defects, while hippocampus-specific knockdown of Ythdf1 or Mettl3, the catalytic component of m6A methyltransferase complex, recapitulates the hippocampal deficiency in adult mice. At the molecular level, transcriptome-wide mapping of m6A sites and RNA binding sites of Ythdf1 on hippocampal mRNAs using crosslinking immunoprecipitation followed by high-throughput sequencing (CLIP-seq) uncovered key neuronal genes, including those involved in synaptic transmission and long-term potentiation. Nascent protein labelling and tether reporter assays in cultured hippocampal neurons revealed that Ythdf1 is critical for initiating a pulse of protein synthesis of target transcripts in a neuronal-stimulus-dependent manner. Collectively, our results uncover a pathway of mRNA m6A methylation in learning and memory, which is mediated through Ythdf1 in response to stimuli.
Project description:N6-methyladenosine (m6A) RNA methylation is implicated in the progression of multiple cancers via influencing mRNA modification. Intersection of RNA-seq, Methylated RNA immune-precipitation (MeRIP)-seq, co-immunoprecipitation, RNA pull-down and MeRIP-PCR were used to identify YTHDF1- modified USP14 and its m6A levels in GC cells. Intersection assays revealed that YTHDF1 promoted USP14 protein translation in an m6A-dependent manner. Our data suggested that m6A reader YTHDF1 facilitated tumorigenesis and metastasis of GC by promoting USP14 protein translation and might act as a clinical therapy for GC.
Project description:In addition to perform the m6A-seq in A549 cells, we sequenced RNA obtained from the immuno-purified complex of YTHDF1 (RIP-seq) to reveal YTHDF1 bound mRNAs, 3,676 genes were shared (m6A-seq+RIP-seq) as high-confident targets of YTHDF1 , which were mapped to cell cycle and tumor (including lung cancer) related signaling pathways in the KEGG pathway database
Project description:N6-methyladenosine (m6A) modification has been implicated in many cell processes and diseases. YTHDF1, a translation-facilitating m6A reader, is not previously shown to be related to allergic airway inflammation. Here, we report that YTHDF1 is highly expressed in allergic airway epithelial cells (AECs) and asthmatic patients, and influences proinflammatory responses. CLOCK, a subunit of the circadian clock pathway, is the direct target of YTHDF1. YTHDF1 augments CLOCK translation in an m6A-dependent manner. Allergens enhance the liquid‒liquid phase separation (LLPS) of YTHDF1 and drive the formation of a complex comprising dimeric YTHDF1 and CLOCK mRNA, which is distributed to stress granules (SGs). Moreover, YTHDF1 strongly activates NLRP3 inflammasome production and IL-1β secretion, leading to airway inflammatory responses, but these phenotypes are abolished by deleting CLOCK. These findings demonstrate that YTHDF1 is an important regulator of asthmatic airway inflammation, suggesting a potential therapeutic target for allergic airway inflammation.
Project description:Emerging evidence emphasizes the important role of tumor neoantigen in generating the spontaneous antitumor immune response and predicting the clinical response to immunotherapies. Despite the presence of numerous neoantigens, complete tumor elimination rarely occurs in majority of patients due to failures in mounting a sufficient and lasting antitumor immunity. Here we show that the durable neoanitgen-specific immunity is regulated by a m6A-binding protein, Ythdf1. In contrast to wild-type mice, Ythdf1-deficient (Ythdf1-/-) mice generate more antigen-specific CD8+ T cell response for persistent tumor control. Loss of Ythdf1 in dendritic cell (DC) results in an enhanced cross-presentation of tumor antigen and cross-priming of CD8+ T cell in vivo. To confirm our observations, we performed Ribo-Seq to analyze the translational efficiency of genes in DCs and performed m6A-seq to locate the m6A sites.
Project description:N6-methyladenosine (m6A) governs the fate of RNAs through m6A readers. Colorectal cancer (CRC) exhibits aberrant m6A modifications and expression of m6A regulators. However, little is known about how m6A readers interpret oncogenic m6A methylome for malignant transformation. m6A reader YTHDF1 was overexpressed by copy number gain/amplification in majority of CRCs. YTHDF1 high expression and CNVs predict increased risk of CRC relapse. Transcriptome profiles of YTHDF1-high tumors exhibit highly metastatic features. YTHDF1 promoted CRC tumor cell and organoid proliferation and enhanced metastasis. Ythdf1 knockout dampened tumor growth in carcinogen-induced CRC model. Through multiomic integration, RhoA activator ARHGEF2 was characterized as the key functional YTHDF1 target based on its m6A and YTHDF1-binding signal, translation efficiency changes, protein correlations with YTHDF1 in clinical samples, and disrupted RhoA features by YTHDF1 knockdown. Moreover, YTHDF1-ARHGEF2 co-regulation was observed in YTHDF1-overexpressing metastatic sites and carcinogen-induced Ythdf1-null CRC tumors. ARHGEF2 overexpression significantly rescued RhoA signaling, tumor cell survival and invasiveness impaired by YTHDF1 knockdown both in vitro and in vivo, further confirming the essential function of ARHGEF2.
Project description:To study the effect of m6A modifications on subcellular mRNA localization we depleted m6A readers Ythdf1, -2 and -3 with shRNAs from mouse primary cortical neurons (mPCN) and sequenced neuritic and somatic compartments in parallel with scrambled shRNA control.